Laser printers are the printers of choice for delivering consistently high-resolution output text and graphics images. When used to print graphic images, laser printers can consistently deliver line resolutions approximating the resolution of photography.
In printing graphic images, a limitation of laser printersxe2x80x94as well as ink jet printers and even copiersxe2x80x94is the ability of the printer to accurately print close to the edge of a sheet of paper. Misalignment between the sheets of paper in a removable printer paper tray and a laser print engine makes it difficult for a laser printer, or for any other printer for that matter, to print edge-to-edge on a sheet of paper. Most laser printers can print as close as ⅙th of an inch away from the edge of a page. A method and apparatus by which a printer can be enabled to accurately align a print mechanism so as to be able to print much closer to the edge of a page on which an image is to be printed, would be an improvement over the prior art. Edge-to-edge printing would enable a printer to print output graphics (e.g. photographs) that more closely resemble a photograph, which usually fills the photographic paper on which it is printed from one edge to another.
There is provided a method and apparatus for aligning a print mechanism, such as a laser print engine or an ink jet print head, to a page so as to enable the print mechanism to print text and images close to the page edge. As paper is fed into a printer, the placement of the paper with respect to the longitudinal travel limits of the print mechanism is unknown.
The method of one embodiment includes the steps of first moving the print mechanism to a left or right travel limit and then printing at least one alignment or registration image or mark beginning at the chosen travel limit, which is sufficiently large so as to be least partially printed onto the pagexe2x80x94even if the page is severely misaligned with respect to the print engine. The print engine or other printing mechanism is then moved to the opposite travel limit whereat the alignment or registration mark is printed again. By comparing the two alignment marks that were printed, the alignment of the page with respect to the print mechanism can be determined. By examining the printed calibration page, which can be printed with an image as well as instructions, a user can enter one or more keystrokes at a printer control panel by which the printer""s print engine alignment can be set.
A page that is perfectly aligned with the print mechanism will bear identical alignment marks at both margins. Print mechanism misalignment with respect to the feed paper is manifested by one alignment mark being greater or larger or otherwise different than the other mark. By manually (or automatically) re-positioning the print mechanism""s starting point so as to cause the print mechanism to print equal amounts of both alignment marks on a page, the print mechanism of a printer can be closely aligned to a page edge thereby enabling the placement of printing much closer to the paper edge, even to the exact edge of a page.